The invention relates to the rehabilitation of deteriorated underground piping.
The prior art teaches several methods of sewer or pipeline rehabilitation, ranging from the excavation and replacement of the damaged pipe section to slip lining, i.e., the insertion of a second pipe of smaller diameter through the existing piping. However, excavation is costly, time consuming, and particularly impractical in congested urban areas, while the smaller pipe employed in slip lining appreciably reduces pipeline capacity.
A recent development in the art teaches a method of insitu pipe repair comprising the insertion therein of a pliable polyester felt sleeve whose inner surface is impregnated with a thermoset resin. The sleeve is inverted as it is advanced through the damaged pipe under hydrostatic pressure. The sleeve is thus turned inside-out, with its resin-impregnated inner surface pressing firmly against the inner walls of the damaged pipe. The water is then heated and recirculated for several hours, whereby the thermoset resin cures to form a new pipe within the original pipe.
Unfortunately, the inverted thermoset sleeve method necessitates procurement and subsequent heating . of prodigious quantities of water. A prolonged curing period is also required, during which the pipeline must be removed from service. Further, the inversion technique is suitable for use with a limited range of pipe diameters and cannot accommodate more substantial and, hence, more rigid reinforcement fibres within the thermoset resin matrix.